Prerequisites for magnetic resonance image-guided interventions and endoscopic surgery

MR Imaging Safety in the Interventional Environment

Interventional MR imaging procedures are rapidly growing in number owing to the excellent soft tissue resolution of MR imaging, lack of ionizing radiation, hardware and software advancements, and technical developments in MR imaging-compatible robots, lasers, and ultrasound equipment. The safe operation of an interventional MR imaging system is a complex undertaking, which is only possible with multidisciplinary planning, training, operations and oversight. Safety for both patients and operators is essential for successful operations. Herein, we review the safety concerns, solutions and challenges associated with the operation of a modern interventional MR imaging system.

The new interventional centre--a multidisciplinary R&D clinic for interventional radiology and minimal access surgery

The National Hospital wanted to coordinate and promote the development of new minimally invasive procedures by structuring collaboration and communication across traditional speciality boundaries. To achieve this, a new hospital department has been established, a 'neutral ground' for working with such clinical applications in multi-disciplinary teams with surgeons, radiologists, cardiologists etc., individually composed for the type of intervention to be performed. The Interventional Centre also represents a full fusion of a modern radiology department with a state-of-the-art operating department, securing the use of relevant imaging technologies, aseptic conditions and options of converting any 'key-hole' procedure to open, conventional surgery within minutes. The Centre represents a new organizational model for such activities. It is also a technology centre, a common 'tool-box' securing better access and higher quality for the use of advanced radiological and surgical technology in our hospital.

The interventional magnetic resonance unit--the minimal access operating theatre of the future?

Interventional magnetic resonance units give the surgeon the potential to use intraoperative imaging to guide the surgical procedure. The advantages of magnetic resonance (MR) over other intraoperative imaging modalities include excellent soft tissue resolution, lack of ionizing radiation and the ability to reconstruct images in any desired plane. Postulated advantages include the ability to confirm adequate tumour resection, reduction in procedure magnitude and complication rate, shortened inpatient stay and the development of novel minimally invasive techniques including the use of thermal energy to destroy lesions. Fully MR compatible anaesthetic and patient monitoring equipment is available. However, before the MR-guided minimally invasive surgery can become a reality, much work is required in the assessment and development of MR compatible surgical instrumentation and equipment. This review describes the testing and development of instruments and equipment for MR image-guided surgery that we have undertaken. We describe the techniques we employ for open and minimal access surgery within this unique environment. The difficulties of operating within such an environment and the safety issues that this engenders are discussed. The current applications of intraoperative MR in the main surgical specialities are reviewed, and possible future areas of development for MR-guided minimally invasive surgery described.

Interventional magnetic resonance imaging

The development of minimally invasive surgical and interventional techniques has created a need for more accurate and sensitive image guidance and monitoring. Magnetic resonance imaging, with its superior soft tissue discrimination and multiplanar facilities, seems the obvious choice for an ideal image-guidance tool. Until recently, the employment of MRI in this role has been prevented by the physical constraints of conventional, closed-configuration machines. The problem has now been overcome by the development of an open design allowing both horizontal and vertical access to the patient in the scanner so that procedures can be performed concurrent with image acquisition. This configuration, together with the use of fast gradient echo sequences which can scan at speeds close to real time, means that a wide range of interventional procedures can be performed with on-line image guidance and monitoring. In addition, the versatility of the open design means that patients can assume physiological positions to allow dynamic joint imaging to be performed. This opens up a whole new field in the understanding of joint pathophysiology. This review article discusses these recent technological developments and their clinical applications. In particular, the potential role in guidance of biopsies, monitoring of thermal ablation techniques and applications in endoscopic surgery is outlined.